ACDelco stands for quality. Get the performance you need with ACDelco products. ACDelco Heavy Duty Flooded Maintenance Free Batteries have a Calcium-Calcium plate construction to resist vibration, shock, and heat. ACDelco 4D and 8D Heavy Duty Flooded Maintenance Free Batteries offer reliable ACDelco quality at an economical price. These batteries have the same Calcium-Calcium plate technology used on ACDelco automotive products and plates designed to withstand longer running applications. These batteries have center line terminals which allow for the greatest installation versatility. Permanently sealed covers and specially designed grid offer excellent vibration resistance. ACDelco products are developed to exceed your performance expectations and deliver the durability you expect.